The present invention relates to a light guiding device of a liquid crystal display, and especially to light guiding device of a liquid crystal display having a liquid crystal module which has the structures for focusing light and reflecting light.
In the front light liquid crystal display, high luminous LEDs are used to replace CCFLs since the LEDs are power saving. Because LEDs are point light sources, if it is desired to convert the LEDs to become uniform light source, the light guiding module illustrated in FIG. 5 is necessary. In using such kind of liquid crystal display, since the light outlet surface 811 of the light guide bar 81 is a plane, light from the LED light source 82 is reflected on the light guiding plate 812 on the light outlet surface 811, and part of light is reflected on the reflecting surface 812 and then reflected on the light guiding plate 83. Since the reflecting light from the light guiding plate 83 travels to the liquid crystal module (not shown) so that the liquid crystal module is luminous. Since the light outlet surface 811 of the light guide bar 82 has a plane shape and has a smaller reflecting angle xcex1, light is easily scattered (the light outlet angle is about xc2x145 degrees) so that a large part of the light is scattered out of the light guiding plate 83. Therefore, much of the light is lost and the liquid crystal display has a bad luminous. Furthermore, in the transferring process, since loss in the transmission of the light, the light is difficult to be transferred to another end of the light guide bar 81. Therefore, the light reflecting to the light guiding plate 83 is not uniform and the illumination of the liquid crystal display is not uniform.
With reference to FIG. 6, a further prior art for improving the illumination of the light guiding module of a liquid crystal display is illustrated. In this prior art, he light guide bar 91 has a larger outer diameter near the LED light source 92, and another end has a smaller outer diameter so as to have a wedge shape. The light outlet surface 93 is extended obliquely. Although this is helpful for reflecting the light of the LED light source 92 to another end of the light guide bar 91 for increasing the uniform of the illumination of the light, while a large part of the reflected light will diffusing out of the light guiding plate 91. As a result, the illumination of the liquid crystal display is not preferred.
Accordingly, the primary object of the present invention is to provide a light guiding device of a liquid crystal display, wherein by the curved surface of the light outlet surface of the light guide bar, reflected light is more uniformly and scattering of the reflected light is reduced. Moreover, the refracting portion of the light guiding plate 21 refracts the light so that the reflecting lights and transmitting light are refracted and concentrated on the light guiding plate. Consequently, the efficiency of light is improved.
Another object of the present invention is to provide a light guiding device of a liquid crystal display, wherein light guiding plate of the light guiding module has two sides which are connected to the two ends of the light guide bar through a respective connecting portion. Therefore, they may be manufactured conveniently.
To achieve above objects, the present invention provides a light guiding device of a liquid crystal display. A liquid crystal module is installed with a light guiding module. The light guiding plate of the light guiding module has a refracting portion at one side. The middle section of the refracting portion is protruded out. Besides, a light guide bar is installed near the refracting portion and faces the side adjacent to the light guiding grooves. The light guide bar has a light outlet surface at the side near the light guiding plate. The light outlet surface 241 is a cambered concave surface. The middle section of the light outlet surface causes a thickness of the light guide bar to be thinner and thickness at two ends of the light guide bar being thicker. The light guide bar has a reflecting surface at a surface other than the light outlet surface; the reflecting surface having a plurality of reflecting grooves. Near the side of the light guide bar different from the side facing the light guiding plate and adjacent to the reflecting surface being installed with a cambered reflecting mask. Two ends of the light guide bar being installed with a respective LED point light source.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing.